Exhaust actuated missile exit door



Dec. 17, 1957 R. T. JOHNSTON EiH-IAUST ACTUATED MISSILE EXIT DOOR FiledOct. 6, 1952 EXHAUST ACTUATED MISSILE EXIT DOQR Robert T.Johnstomlacific Palisades, Califi, assignor to Northrop Aircraft,.1nc.,Hawthorne, Calif, a corporation of California Application October 6,1952, Serial No. 313,271

1. Claim. (Cl. 89-1.7)

This invention relates to rocket launching devices and more particularlyto a rocket launching device in which rockets are mounted for firingfrom within a streamlined structure of an airplane, such as a wing tippod or wing nacelle, in which a portion of the streamlined structure isindirectly moved by thrust of a rockets exhaust gas to provide a clearforward course for the rocket.

In military planes rockets are normally mounted on the underside oftheir wings with their axis parallel with the longitudinal center lineof the plane. This method is objectional as it increases the frontalareas of the airplane and materially increases its parasite drag.

It is, therefore, an object of the present invention to provide a rocketlaunching device ideally suited for use with an airplane.

Another object of the present invention is to provide a streamlinedstructure completely surrounding a rocket and.

its associated launching tube except at such time as it is being firedand discharged from the above structure.

Another object of the present invention is to provide a movable surfaceahead of a rocket launching tube, the surfacebeing movedupon firing of arocket from the tubeby the rockets exhaust gas to a position in which itprovides a clear course for the forward movement of the rocket.

Other objects and advantages of the present invention will be apparentfrom the following description forming a part of this specification,however, the invention is not limited to the embodiment herein describedas various forms may be adapted within the scope of the appended claim.

Throughout the specification andclaim of the present application theWord rocket includes both guidedancl.

unguided reaction driven or self-propelled missiles.

The invention may be more fully understood by reference to theaccompanying drawings, wherein:

Figure 1 is a perspective view of an airplane having wing tip pods inwhich rocket launching tubes having movablecover elements, of the typedisclosed in the present invention, are incorporated.

Figure 2- is a front elevational view of the wing tip pod of Figure lshowingthelaunching tube covers in their closed position.

Figure 3I- isa-sectionalview of the wing tip pod of Figure 2 taken onthe line 3-3 thereof.

Figure 4 is a cross sectional view of the wing tip. pod of Figure 3'takenon the line 4'4 thereof.

Referring to Figure l a jet driven' airplane 1 is fitted with wing tippods 2, their forward portion 3 being utilized for mounting rocketswhile engine fuel is carried in a plurality of generally cylindricaltanks in the aft portion 5 of the pod 2.

A bulkhead or fire Wall 6, comprising a circular plate of heat resistingmaterial, is positioned between the fore and aft portions of the pod.The circular faces of the bulkhead are normal to the longitudinal axisof pod 2 and in this position effectively shields fuel in the fuel iretanks 4 from heat which may be radiated from the exhaust gases ofrockets fired from within the forward portion of the pods.

The forward portion 3 of the wing tip pod comprises inner and outerconcentric generally cylindrical members 7 and 8, the members beingjoined at their forward ends to provide a streamlined-contour. The outersurface of the fore and aft portions of the Wing tip pods-arecontinuous, a streamlined structure is thus provided.

The outer cylindrical surface of the forward portion of the pod isprovided with a plurality of circumferentially spaced generallyrectangle shaped openings 9' when viewed normal to the surface of thepod. Threesuch openings are shown in the present embodiment, eachprovided with a cover or closure element 10 capable of closing theopenings and maintaining a flush relationship with the outer cylindricalsurface of member 3, shown by solid line construction in Figure 3. Anaid in position ing and retaining the cover in its closed position isprovided by a ledge 11 extending around a major portion of itsperiphery, in the covers closed position the ledge is'in abuttingrelationship with the inner surface of cylindrical member 8.-

The rocket launching tubes 12 as shown in the present embodiment arecruciform in cross section, each arm portion 13 providing a passagewayfor a fin member 14 of the rockets 15. The launching tubes are equallyspaced circumferentially within the annular chamber 16 defined.

by the generally concentric cylindrical members 7 and 8, the axis ofeach tube being parallel with the longitudinal axis of the pod. securelyheld in position by means of apertures in a circular plate 17, saidplate being positioned a short distance. ahead of bulkhead 6, the tubesare secured longitudinally to concentric members 7 and 8 by means oftheir arm portions 13. Tubes 12 extend forward from plate 17 to a-point'adjacent the aft end of covers 10, suf ficient clearance being providedbetween the forward end of the tubes and the covers to allow the latterto swing-inwardly, in a manner to be presently described. Conduits 18coinciding with the aft ends of tubes 12, extend'rearwardly andlaterally to exhaust ports 19 located in the side wall of the podforward of bulkhead 6, to provide passageways 20-for the flow of exhaustgases. The passageways change from a cruciform cross section adjacentthe launching tubes to a circular cross section a short dis tance aft ofsaid tubes.

Additional rockets and'launching tubes, utilizing operating mechanism asdisclosed in U. S. applications 303,381, dated August-8, 1952, and804,351, dated August 14,- 1952', may be mounted within cylinder 7 andin'the space defined by cylinder 8 and arm portions 13 of adjacentlaunching tubes, respectively, asshown in Figured;

In the present embodiment rocket propelled missiles are fired fromlaunching tubes 12' of the character-having radar or similar sensitiveequipment mounted in their nose portions. It is imperative that theirnose portions do not come in contactwith any structural elements, as

they move forwardfrom their'resp ective launching tubes, if theequipment mentioned above is to function properly.

To provide a free forward course'for a rocketthe' cover 10- is" mountedfor movement'inwardlyfromitsclosed position. To this end pivot members22 and 23 are provided, the above members are mounted between four setsof laterally spaced lugs which are secured to the inner surface of cover10 and the outer surface of cylinder 7. Pivot member 22, which isgenerally H-shaped in configuration, extends between lugs 24 and 25 andis pivotally attached thereto by means of pins 26 which extend betweeneach set of lugs, said lugs being positioned near the forward end of thecover 10. Pivot members The aft end of tubes 12 are 23 extend betweenlugs 27, secured to cylinder 7 approximately opposite the mid-point ofthe opening 9, and lugs 28 positioned on cover 10 near the aft end ofthe openings 9, the above members 23 are pivotally secured to lugs 27and 28 by means of conventional pins. A pair of helical springs 30 aresecured between a non-movable structural element of pod 2 and a lug 31,the latter extending generally at right angles to pivot members 23.Springs 30, which are under tension at all times, provide means forholding cover 10 in its closed position until acted on by an externalforce and for returning the covers from their open to their closedposition. The cover mounted as described above, is movable from a closedposition to a fully open position, the latter being shown by phantomconstruction in Figure 3. A stop 32 is provided on cylinder 7 to limitthe inward movement of the cover.

Positioned in each passageway 20, directly aft of rocket 15, areactuating flaps 33 swingably mounted to move between a closed and openposition, shown by conventional and phantom construction, respectively,in Figure 3. Flaps 33 are fixedly secured to hinge pins 34, the latterbeing mounted for rotary movement in bearings 35 positioned externallyof conduits 18. An arm 36 is keyed to pin 34 and moves through an equalare as the flaps move between their open and closed position.

A bellcrank 37 is mounted in a bearing support 38 located on the forwardside of plate 17. The bellcrank rocks about an axis normal to a planecontaining both the longitudinal axis of a rocket 15 and pod 2, botharms of the bellcrank are also positioned generally in the above plane.A connecting member 39 extends between arm 36 and the aft arm 40 of thebellcrank, the member 39 being pivotally attached to the end portions ofthe arms by means of conventional hinge pins.

vA Bowden wire assembly 41 provided with attaching end portions 42extends between the bifurcated end por tion of arm 43 of the bellcrankand the mid-portion of hinge pin 26 located adjacent cover 10. TheBowden wire assembly is positioned adjacent the outer surface ofcylinder 7 and is attached thereto by means of a plurality of clips 44to the wall of said cylinder.

A rocket is supported in firing position within its launching tube bymeans of a conventional launcher 45. A shear pin 46 retains the rocketin its tube and in a-fixed position relative to its launcher until suchtime as it is fired. The launcher contains an umbilical connection plug47 by means of which electrical impulses, including impulses for firingthe rocket are transmitted thereto, however, the particular type oflauncher constitutes no part of the present invention, the type shownbeing illustrative only.

Diagonal slots 48 extend rearwardly in the surface of cylindrical member8 from each corner of the openings 9, the above slots provide clearancefor the rockets fins as the rocket moves forward from its launchingtube.

In operation the three rocket propelled missiles 15 are loaded in theirrespective tubes from the forward end of said tubes, this operation isaccomplished after the covers 10 have been moved to their open position.At the same time rockets are also loaded interiorly of cylinder 7 andbetween the arm positions of adjacent tubes 12.

Individual frangible plugs 21, positioned in the forward end of thelaunching tubes located interiorly of cylinder 7, preclude the flow ofair therethrough prior to firing.

Upon the firing of a rocket the thrust from its exhaust gas exceeds 1200pounds, this exceeds the thrust required to shear pin 46. Before pin 46is sheared the thrust of the rockets exhaust gas impinging on flap 33 issufficient to swing it from its closed toits open position. The swingingmovement of flap 33 is transmitted to cover 10, through connectingmember 39, bellcrank 37, and Bowden wire assembly 41, causing the coverto move from its closed position to its fully open position, in thelatter position a clear forward course for the rocket is provided.Actual launching data discloses that the thrust of the rockets exhaustgas is more than adequate, in fact allows a good margin of safety, tomove cover 10 into its fully open position prior to the shearing of pin46. The same data discloses the thrust of the rockets exhaust gas issufiicient to retain cover 10 in its fully open position during therockets exit from pod 2.

From the above disclosure it is apparent there is provided a rocketlaunching device capable of accomplishing the various objects set forthabove. While in order to comply with the statute, the invention has beendescribed in language more or less specific :as to structural features,it is to be understood that the invention is not limited to the specificfeatures .shown, but that the means and construction herein disclosedcomprise a preferred form of putting the invention into effect, and theinvention is therefore claimed in any of its forms or modificationswithin the legitimate and valid scope of the appended claim.

What is claimed is:

In an airplane having a leading edge surface, the combinationcomprising: a rocket launching tube mounted within the airplane andhaving a forwardly-facing open end; means defining a discharge openingin the surface aligned with said tube; a cover for said opening mountedon the airplane for swingable movement between a closed position whereinsaid cover constitutes an extension of the surface and an open positionwherein a rocket fired from said tube can pass freely through saidopening; resilient means urging said cover to said closed position; aconduit in the airplane rearwardly of said tube providing a passagewayfor exhaust gases of a rocket fired from said tube; an actuating flapswingably mounted in said conduit; linkage means connecting said flap tosaid cover to move the latter from said closed to said open position onthe impingement of the gases on said flap; and detent means in said tubeengageable with a rocket therein to retain the latter in said tube, saiddetent means being releasable by a predetermined thrust of a rocketbeing fired from said tube, whereby forward movement of a rocket isdelayed until said cover moves to its said open position.

References Cited in the file of this patent UNITED STATES PATENTS2,395,435 Thompson et al Feb. 26, 1946 2,445,235 Myers July 13, 19482,451,522 Uhl et a1. Oct. 19, 1948 2,470,120 Walker May 17, 19492,481,542 Schuyler Sept. 12, 1949 2,517,333 Motley- Aug. 1, 1950 FOREIGNPATENTS 804,838 France Nov. 3, 1936 924,013 France July 24, 1947

